Ping pong ball



FIG. 1 is a front view of the ping pong ball of my new design;

FIG. 2 is a rear view;

FIG. 3 is a left side view;

FIG. 4 is a right side view;

FIG. 5 is a plan view; and,

FIG. 6 is a bottom view. 

The ornamental design for a ping pong ball, as shown and described. 